To what pressure are you filling your PST 104s to?

[Scrappy]

I have heard that you can consistantly overfill PST 104s (3000 psi) and still pass hydros. I was just wondering if you guys who have these tanks, and have had for a while know anything about this.


As a side note: I got to see my first big shark the other day. As we were swimming along we happened upon a 10 - 12 foot thresher or nurse shark. I was so excited that I barely got a picture of it. I should be getting them developed Monday... can't wait.

Scrappy :D

[jbd]

My diving buddy just purchased some PST 104's. Its my understanding that the max fill is 2640 psi. You might pass the first hydro but maybe not the 2nd or 3rd etc, etc. You may not get the full useful life out of the tanks.

[Campana]

I just got back from Florida, cave country. My BELIEF is that it is very common to fill the tanks to 3,000 and beyond with little ill effect. Myself, I have Fabers. They are advertised as being rated for 10,000 fills to 4,000 psi, even though they too are rated for 2650 in the US.

I BELIEVE that your tanks could be overfilled to 3,000 and still pass hydros just fine.

Disclaimer: This is just stuff I've heard. You should get much more informed opinions than mine on almost all subjects, but maybe especially this one.

[caverkevin]

You'll be scared poopless before you overfill pst104's. I have personnal fill those cylinder over 50% with no problems. When I worked in cave country I saw many sets with multiple re-hydro test stamps, on old 104's. The new versions a built like armored tanks compared to the old one's. I would not worry if they got fill over the rated pressure a little bit. Just stack your disks or get some solids to plug your valve. If you are not filling your own or in cave country, chances are you will not get fills over the rated pressure.

KLJ

[Bob]

Just a note on the PST 104's. It's not uncommon for cavers and rec divers alike to overfill by as much as 500 to 600 PSI. It's a fact of life. :tree: Bob

[jimholcomb]

Routinely fill mine to 3200-3500. Has been as high as 4000 before without death and destruction. Just got them hydroed with no problems.

[Divesherpa]

4100 PSI in the PST 104's almost every day. The people in Cave Country claim to have never had a 104 fail hydro. This is a shop where 3800 is the standard fill and they fill a *lot* of bottles

[voidware]

My shop will fill their rental lp steel tanks to 3200. They will fill it higher if you have DIN, bring in your own tank, or are special, like me. I have had em filled up to 3800 before.

brandon

[Norm]

I once saw 4800 psi in a set! (I guess that saves time on hydro's huh?)

[Rick Murchison]

2640.
Rick

[D.I.R.Lizard]

I have been told numerous times they are rated @4000 in Europe.
But the states only rated @2640.

I generally fill mine to 3000 or 3200, and have seen them at 4000.

[WYDT]

Usually get 3600 in mine. I know some people that have 104's that are nearly 20yrs old and get overfilled every day. I've NEVER heard of one failing hydro. I'm not saying it hasn't happend just that it's not a common occurance.

Those 104's will be around longer than you overfills or not. Just make sure you shim the burst disk (or double them up). Also make sure you keep any mositure out of them. Rust is much more dangerous to steel tanks than filling them above the "DOT" rating.

DSAO!

[trymixdiver]

i dont know about the PST but i am guilty of over filling my Fabers. I usually fill them to 3500psi. I did this for a year and i just got them hydros last month, no problems.

Andy

[maddiver]

Originally posted by caverkevin
You'll be scared poopless before you overfill pst104's.
KLJ

Man that's for sure....you used to run the old mouth and force my precious beauties (95s) to 3800 and whine when I only wanted 3200 in them! They don't let you fill tanks in Michigan like they did at Ginnie do they?

Hollar at me when you get back down to cave country. :)

[ninja]

We overfill for our trimix dives all the time!! 3000 to 3500 hundred is not uncommon;)

We have pst 72's from the mid 60's at the shop and they are rated to 2250psi and are consitently filled to 2500 or so!!

Pst steel makes the best tanks that i have ever seen:)

i also have Heiser 104's and you thought pressed steels were heavy these bad boys have an inch and a half of steel wall.I Crank em up all the time!!:eek:

Double disk the tanks or plug em and get on with the diving.

Len

[Bob]

The PST 104's are the best tanks going. I have two that are ten years old, and a normal fill is 3200 psi. and have had no problems with hydro. I bought two more about a year ago. No reason to dive with anything but steel. :tree: Bob
:tribute:

[maddiver]

Well.........................PSTs are pretty good.

But I would be hesitant to suggest there is no reason to dive with anything but steel. How about ow with wesuit? What about stages? Both of those applications the correct tool for the job is alum tanks.

PST are perfect doubles for fl caves with drysuit but they are not practical in other areas (such as the Yucatan) where you can dive forever on double 80s with a wetsuit and also avoid the potential for overtaxing the entry and exit ladders (that already look shakey).

They are pretty bulletproof as far as hydros and overfills are concerned.






Originally posted by Bob
The PST 104's are the best tanks going. I have two that are ten years old, and a normal fill is 3200 psi. and have had no problems with hydro. I bought two more about a year ago. No reason to dive with anything but steel. :tree: Bob
:tribute:

[Bob]

Well...
Contrary to the misconcertion that one can't dive open water with a wetsuit and steel, you can. I should say that I taylor my gear to where I dive and my diving is in Florida and the Carribean. I regulary dive with a 3mil wetsuit and my steel tanks. Most of the guys I dive with do the same. I have four AL 80's and occasionally I use 'em, but I just hate that extra four pounds per tank I have to carry just to use AL, don't you? Steel tanks have superior bouyancy charateristics, they will carry more air, and if properly cared for, last much longer than AL. There is a interesting thread here on the board about how durable AL. tanks are. It makes for some good reading. Dive safely. :tree: Bob.
:tribute:

[maddiver]

Bob-

While it is physically possible to dive steels with a 3mm wetsuit in ow (and it at first glance has many compelling reasons) the real issue I have with it (and I dm'ed on west coast of FL for years) is that you have no redundant buoyancy device (ie drysuit) and essentially no ditichable weight. If if you can swim them up it loads you pretty heavily. Do me a favor and dive your current rig and at 100 ft on your next wreck dive (when your wetsuit is paper thin) let all the air out of your bc...I mean every last bit and try just to swim up to 70 ft. Check you press gauge before and after. What would be the same situation using an alum set of tanks?

As divers we tend to think about getting down and staying down hence the value propositon of lp steel tanks for weight and volume, but not enough about getting back up.



Originally posted by Bob
Well...
Contrary to the misconcertion that one can't dive open water with a wetsuit and steel, you can. I should say that I taylor my gear to where I dive and my diving is in Florida and the Carribean. I regulary dive with a 3mil wetsuit and my steel tanks. . :tree: Bob.
:tribute:

[maddiver]

------------

[Scubaroo]

A bit off thread... but I found this gem of a quote while reading an Australian dive site, regarding the "true" bursting pressure of some aluminum tanks that had failed hydros....



at the test station, we had some ali cylinders that had been failed due to folds / cracks in the neck etc... so when bored, decided to "pump up" a few... they split down the sides, none at LESS than 500 bar... tried 6 cylinders... one made it to 650...
500 bar is about 7250psi...
650 bar is about 9400psi...

:boom:

[ninja]

Originally posted by maddiver
Well.........................PSTs are pretty good.

But I would be hesitant to suggest there is no reason to dive with anything but steel. How about ow with wesuit? What about stages? Both of those applications the correct tool for the job is alum tanks.

PST are perfect doubles for fl caves with drysuit but they are not practical in other areas (such as the Yucatan) where you can dive forever on double 80s with a wetsuit and also avoid the potential for overtaxing the entry and exit ladders (that already look shakey).

They are pretty bulletproof as far as hydros and overfills are concerned.

Well I guess their is no diving anywhere else in the world!! The Great lakes you will use a dry suit and even with your stage bottles you need the extra ballast ! Fabers suck for this and aluminum are not even an option! Bring on the 104's the heavier the better!

Len

[Rick Murchison]

Originally posted by maddiver
Bob-

While it is physically possible to dive steels with a 3mm wetsuit in ow (and it at first glance has many compelling reasons) the real issue I have with it (and I dm'ed on west coast of FL for years) is that you have no redundant buoyancy device (ie drysuit) and essentially no ditichable weight.
Au contraire, my young friend... there are many ways to assure redundancy in lift - the easiest is to carry a lift bag. No sweat.
Rick

[Lost Yooper]

I fill mine to 3300-3500psi routinely (both PST and Fabers).

Mike

[Uncle Pug]

Hey Yooper Duper...
Glad you're still alive and kickin' !!!
Long time no post :D

[maddiver]

Ok rick- I'm not going to bite....real hard on this one until I understand where you are going?

Do you mean that you would dive in deep ow with say a 3mm suit and double pst 104's and taking your lift bag and consider this adequate and 'optimal' configuration (in terms of buoyancy needs)?

Feel free to make that 3mm a 6.5mm or whatever for discussion sake. I am real interested in how your lift bag could be of great use **immediately** like within 5 secs if your wing came apart in really deep ow. Would a drysuit with this tank configuration not be more appropriate? I'm not saying that you haven't been doing it like this for years and getting away with it, or that you have to stop if you have been...merely looking for the logical support. Why not go to alum 80s for ow if you choose the wetsuit? If you choose a drysuit then by all means go with the steels (doubles only not stage steel).

I really doubt you could swim up (more like just maintaining your depth) a set of 104s with a 3mm wetsuit and deploy a lift bag without major co2 retention and heavy exertion/sac increase but if you have actually tried this to prove to yourself you can do it (ie no gas in your wing at 100' +) I would love to hear about it. Certainly I defer to your experience on this one as I have never worn 104s and wetsuit in ow or tried the method which you suggest.


Please explain to us in detail the use of a lift bag (and whether it is closed or open celled) and why it is appropriate as your primary source of back up buoyancy. Where to store it? How to deploy it in an emergency etc...


Originally posted by Rick Murchison

Au contraire, my young friend... there are many ways to assure redundancy in lift - the easiest is to carry a lift bag. No sweat.
Rick

[caverkevin]

I remember the days before I knew any better. Diving 104's with wetsuits. Open ocean, 130 feet, 5mm and double 104's. I had a dive-rite super wing, no problems, so I felt safe. Then diving caves with a with a two piece 7mm, I lost both cells on that super wing. Lucky I was able to crawl back to the surface. Key word 'crawl' not 'swim'!!!

I would be REALLY careful if your last ditch plan is to ride to surface on a lift bag. Most everyone I have ever heard of using this method get to take another ride, a chamber ride.

Don't take me wrong, 104's are great tanks. I use mine a bunch. But take a look at the context here. Do you really need excess of 200 ft^3 of gas for a 100 foot dive. This would be something to evaluate!!!

KLJ

[maddiver]

Kevin-

As always, thanks for a logical and well experienced answer that clearly spells out the issues associated with this thread. On a side note, I did see this guy carrying a lift bag in a cave on my last Yucatan trip. He was going to use it to 'back up his bc' in there.


Originally posted by caverkevin
I remember the days before I knew any better. Diving 104's with wetsuits. Open ocean, 130 feet, 5mm and double 104's.......Then diving caves with a with a two piece 7mm, I lost both cells on that super wing. Lucky I was able to crawl back to the surface.
KLJ

[caverkevin]

On a side note, I did see this guy carrying a lift bag in a cave on my last Yucatan trip. He was going to use it to 'back up his bc' in there.

This made me think of the lady in the TV ad "help! I've fallen and I can't get up". Instead this time, "Help! I've over-inflated my lift bag and I am stuck to the ceiling".

You have to be kidding me on this one. A lift bag for a bail-out plan in the caves. Yucatan no less. Next you are going to tell me he was wearing double 104's, steel stage bottles and a 3mm shorty.

This is some crazy stuff, using lift bags for back-up bc's. I wonder where this idea started. I can't think of any training manuals I have ever seen it printed in. Sounds to me like something a dive instuctor that does no real diving, would tell another diver that does not know any better.

KLJ

[maddiver]

Nope- this guy had double alum 80s and a SS backplate with the pocket thingy (kind of weird to see with a lift bag pooched up in it getting ready to go in the cave). Full Suit- I guess to be atleast a 5mm. No stage, no deco bottle. I don't know if those Halcyon Closed cell bags come with Speleothem induced damage warranties?

Had I remembered the camera......


Originally posted by caverkevin

This made me think of the lady in the TV ad "help! I've fallen and I can't get up". Instead this time, "Help! I've over-inflated my lift bag and I am stuck to the ceiling".

You have to be kidding me on this one. A lift bag for a bail-out plan in the caves. Yucatan no less. Next you are going to tell me he was wearing double 104's, steel stage bottles and a 3mm shorty.

KLJ

[padiscubapro]

Originally posted by jbd
My diving buddy just purchased some PST 104's. Its my understanding that the max fill is 2640 psi. You might pass the first hydro but maybe not the 2nd or 3rd etc, etc. You may not get the full useful life out of the tanks.

I have a set of faber 95s that so far has been through 3 hydros without fail all times have come back with the + stamp on them. For most dives they are filled to 3500(unless I go to a place that doesn't overfill), but they have had numerous 4000 psi fills.

I would say I got my money's worth out of the tanks already....
The tanks have never shown any internal rusting, and have a full fill when stored over the winter.








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